The present invention relates to a drive shaft for a machine tool, for example a core drilling machine, connectable to a drilling tool, in particular to a drill bit, containing a cavity extending substantially over the entire length of the drive shaft and along the axis of rotation which contains at least one inflow opening through which water can be fed along the drive shaft into the drilling tool.
Moreover, the invention relates to an insert device for insertion and positioning in a cavity of a drive shaft.
A water supply unit is an essential and indispensable requirement for virtually all core drilling work as well as for various other work with large and high-performance machine tools (such as, e.g., saws, cutting wheels, or similar). In particular when using a core drilling device for drilling holes in mineral rock by means of a drill bit put into rotation by the core drilling device, it is absolutely necessary to rinse the drill bit. The rock removed when drilling cores and the resulting dust in the form of drilling mud are washed out of the drill bit and out of the bore hole by means of the water used for rinsing. The drill bit would overheat within a very short time if the drilling mud were not washed away and would become fixed in the bore hole such that further drilling would no longer be possible.
A water supply unit for use with a machine tool, such as, for example, a core drilling machine according to the prior art is for example disclosed in the German patent application DE 10 2006 035 345 A1.
The core drilling devices used for core drilling work are often very high-performance in nature and accordingly have high energy consumption. Moreover, the heat development during the execution of core drilling work in core drilling devices poses a considerable problem. Excessive heat development in the interior of a core drilling device can notably reduce its performance and thus the efficiency of a core drilling device. It is also possible for this to lead to permanent damage of the entire core drilling device or individual components. However, there is also the danger that a user of the core drilling device may injure themselves on an excessively heated outer wall which is caused by the heat development in the interior of the core drilling device.
It is therefore the object of the present invention to solve the previously-described problems and in particular to make available a drive shaft for a machine tool, for example a core drilling tool, connectable to a drilling tool, in particular to a drill bit, by means of which damage to the machine tool as well as heat-related injuries to the user can be efficiently prevented. Moreover, an insert device is made available for insertion and positioning in a cavity of a drive shaft by means of which damage to the machine tool as well as heat-related injuries to the user can be efficiently prevented.
To this end, a drive shaft is provided for a machine tool, for example a core drilling machine, connectable to a drilling tool, in particular to a drill bit, containing a cavity extending substantially over the entire length of the drive shaft and along the axis of rotation wherein the cavity contains at least one inflow opening through which water can be fed along the drive shaft into the drilling tool.
The drive shaft is characterized according to the invention in that an insert device is provided in the cavity through which, to cool the drive shaft, the water is guided first in a first direction and then in a second direction, wherein the insert device contains a first curved guide element as well as a second curved guide element for separating the water which is guided in the first direction from the water which is guided in the second direction, and wherein the cross-sectional area of the first curved guide element is designed point-symmetrically about a center longitudinal axis to the cross-sectional area of the second curved guide element.
The water, which is actually provided only for rinsing the drill bit, is hereby efficiently used for cooling the drive shaft and then for cooling the core drilling device. By guiding the water into a first and a second direction, the water is guided for longer through the cavity of the drive shaft whereby greater heat absorption can be generated by the water and thus improved cooling. Due to the curved configuration of the first and second guide element, improved sealing can be achieved from the insert device to the cavity of the drive shaft.
According to one advantageous configuration of the present invention, it may be possible for the insert device to contain a support element to support the insert device in the cavity. By using the support element, improved support of the insert device in the cavity can be ensured.
According to a further advantageous embodiment of the present invention, it may be possible for the insert device to contain at least one positioning element which can be engaged into a corresponding positioning opening on the cavity and whereby a relative movement between the insert device and the drive shaft is prevented.
According to an additional advantageous embodiment of the present invention, it is possible for the insert device to contain at least one separation wall element to guide the water in the first direction as well as to lock the insert device in the cavity. As a result, the water, which enters the cavity, flows in a predetermined flow direction.
With regard to the insert device, the object is achieved by the insert device being designed for insertion and positioning in a cavity of a previously described drive shaft.
Further advantages emerge from the following figure description. Different exemplary embodiments of the present invention are represented in the figures. The figures, the description, and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them to form suitable further combinations.